In short. Bingbot is Bing's web crawler, whose requests can be verified through DNS lookups, Bing's IP list or the Verify Bingbot tool.

Definition: Bingbot is Bing's web crawler, a program that requests web pages to find new and updated content for processing in Bing's search index.

Key facts

As of 17 October 2026, Bing's crawler overview identifies Bingbot as its standard crawler and documents several user-agent strings.
Bing's verification instructions require a reverse DNS (Domain Name System) lookup ending in search.msn.com, followed by a forward lookup that returns the original IP address.
Bing's indexing guidance says submitted pages and sitemaps still require crawling and assessment before appearing in the index.
Bing's overcrawling guidance documents support for crawl-delay in robots.txt and for the Crawl Control feature when that directive is absent.

What does a Bingbot request look like?

A user-agent string is the identifier a crawler sends with a request. Bing's crawler documentation includes this Bingbot string:

Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)

The same documentation lists desktop and mobile strings containing a browser version placeholder, W.X.Y.Z. Bing says it regularly updates its page rendering engine to the most recent stable Microsoft Edge version and substitutes the version it uses into that placeholder.

Bing warns that user-agent strings are easy to spoof. A matching identifier in a server log therefore calls for verification of the requesting IP address before it is treated as authentic Bing traffic.

How is a request verified?

DNS, the Domain Name System, supports lookups between hostnames and IP addresses. Bing's verification procedure starts with the requesting IP address recorded in the server log:

Perform a reverse DNS lookup, which obtains a hostname from the IP address. Check that the hostname ends in search.msn.com.
Perform a forward DNS lookup on that hostname. Confirm that it resolves back to the original IP address.

The documentation names nslookup for Windows and host for Linux. It also offers comparison against Bing's published IP address list and instructs operators to refresh that list daily because it can change at any time.

Bing's Verify Bingbot help page describes a browser alternative: enter the requesting IP address in the tool, then select Submit or Verify to obtain a verdict about whether it belongs to Bing.

How do crawling controls affect indexing?

A robots.txt file gives crawlers instructions about access to a website. Bing's overcrawling documentation provides this example for reducing the request rate:

User-agent: Bingbot
Crawl-delay: 5

Bing describes this setting as a five-second window during which Bingbot can crawl one URL. The same guidance recommends lowering crawl speed during busy hours through Crawl Control and verifying that traffic is authentic before treating it as a Bingbot overcrawling issue.

For indexing checks, Bing's indexing help points to URL Inspection to assess whether Bingbot can crawl a page. It also identifies incorrect robots.txt rules as a possible obstacle to crawling. Submitted URLs still pass through Bing's crawling and assessment process before inclusion in its index.

FAQ

Can I verify Bingbot from its user-agent string alone?

Bing's crawler overview warns that the string can be faked. You can verify the requesting IP address through Verify Bingbot or the documented DNS procedure.

How often should I refresh a Bingbot IP list?

Bing's verification instructions say to refresh the list daily. The list can change at any time.

Sources

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